Xgeva is a monoclonal antibody that targets a protein involved
in cancer-related bone destruction called human RANKL. Other
FDA-approved drugs for similar conditions include Zometa
(zoledronic acid) and Aredia (pamidronate disodium).

Xgeva is not approved for patients with multiple myeloma or
other cancers of the blood.

"Bone metastases represent a major cause of pain and suffering
in patients with cancer and can affect a patient's quality of
life," said Richard Pazdur, M.D., director of the Office of
Oncology Drug Products in the FDA's Center for Drug Evaluation and
Research. "Xgeva has a different mechanism of action than currently
approved drugs aimed at reducing bone complications from
cancer."

Xgeva's safety and effectiveness were confirmed in three
randomized, double-blind clinical studies in 5,723 patients
comparing Xgeva with Zometa. One study involved patients with
breast cancer, another in patients with prostate cancer, and a
third included patients with a variety of other cancers.

The studies were designed to measure the time until occurrence
of a fracture or spinal cord compression due to cancer or until
radiation or surgery for control of bone pain was needed.

In patients with breast or prostate cancers, Xgeva was superior
to Zometa in delaying SREs. In men with prostate cancer, the median
time to an SRE was 21 months with Xgeva compared to 17 months with
Zometa.